Smart Fortwo Fluids & Specs Quick Reference — 450, 451, 452, 453, 454

Easy 5 min lookup Smart Fortwo 450 Smart Fortwo 451 Smart Roadster 452 Smart Fortwo 453 Smart Forfour 454/453

Service interval: Use as a quick reference; verify final spec in the workshop manual for your year and engine

What this is and why it matters

This is a quick-reference summary, not a service procedure. The right fluid spec on a Smart matters more than on a generic car because the engines are small, the tolerances are tight, and the platform crosses two manufacturers — Mercedes-spec on 450 / 451, Renault-spec on 453. Mixing those up is the most common mistake first-time Smart owners make.

For each fluid, the spec is what matters. Brand is secondary. Capacities are approximate — they vary slightly by year, build, and whether you got the filter fully drained. Always check the level after refill and adjust.

How to use this reference

Find your model in the table.
Read the spec column (this is the non-negotiable part).
Use the capacity column as a starting point — fill to about 0.3L below it, run the engine, then top off based on the dipstick or sight glass.
When in doubt, check the workshop manual for your specific year and engine.

Engine oil, coolant, brake fluid, transmission

System	Fluid spec	Capacity	Notes
Engine oil — 450 (0.6L / 0.7L gasoline)	5W-40 ACEA A3/B4	~3.0L with filter	Mineral OK on early cars; semi-synthetic typical now
Engine oil — 450 CDI (0.8L diesel)	5W-40 low-SAPS / MB 229.31 or 229.51	~3.5L with filter	Diesel; verify in workshop manual
Engine oil — 451 NA / Brabus (M132 1.0L petrol)	5W-30 ACEA C3, MB 229.51 approval	~3.4L with filter	Mercedes-spec required; do NOT substitute Renault spec
Engine oil — 451 CDI (diesel)	low-SAPS 5W-30, MB 229.51	~3.7L with filter	Diesel; verify for your engine
Engine oil — 453 (0.9L turbo / 1.0L NA)	5W-30 Renault RN0700 (NA) / RN0710 (turbo)	~3.5L with filter	Renault-spec, NOT Mercedes-spec
Engine oil — 452 Roadster	5W-40 ACEA A3/B4	~3.0L with filter	Same family as 450
Engine oil — 454 Forfour (Mitsubishi-platform)	5W-30 / per workshop manual	varies	Pre-453 Forfour; verify in manual
Coolant — 450 / 451 / 452 (Mercedes platform)	Mercedes blue 326.0 (or MB 325.x equivalent)	~4-5L	Do NOT mix with green or pink
Coolant — 453 (Renault platform)	Renault Type D coolant	~4-5L	Do NOT mix with Mercedes blue
Brake fluid — 450 / 451 / 452	DOT 4	~0.5L for full flush	Confirm on the reservoir cap
Brake fluid — 453	DOT 4 LV (low viscosity)	~0.5L for full flush	LV spec is on the reservoir cap
Transmission — 451 automated manual (5-speed)	sealed, no service	n/a	Service is teach-in / adaptation, not a fluid change
Transmission — 453 DCT (twinamic)	Getrag DCT-spec fluid	~5-6L per service	Star Diagnosis fill-level required for proper service
Transmission — 452 / 454 manual	Mercedes-spec gear oil (verify in manual)	~1.4L	Verify spec for your build
Differential — 451	sealed, no service	n/a	—
Power steering — 453	electric (no fluid)	n/a	EPS — no fluid system
Windshield washer	mix per climate	~2L	Use methanol-free formula in cars with rear washer to protect plastic lines

Tire pressures (cold, base load)

These are general factory base-load recommendations. Verify against the door-jamb sticker on your specific car. Smart's spec is staggered — fronts run lower than rears because of the rearward weight bias.

Model	Front (cold)	Rear (cold)	Notes
Smart Fortwo 450	28-30 psi (1.9-2.1 bar)	33-35 psi (2.3-2.4 bar)	Verify on door jamb
Smart Fortwo 451 NA / Brabus	32 psi (2.2 bar)	36 psi (2.5 bar)	Brabus and high-load specs higher
Smart Fortwo 453	33 psi (2.3 bar)	38 psi (2.6 bar)	Verify on door jamb
Smart Roadster 452	28-30 psi (1.9-2.1 bar)	33-35 psi (2.3-2.4 bar)	Verify in owner's manual
Smart Forfour 453	33 psi (2.3 bar)	36-38 psi (2.5-2.6 bar)	Verify on door jamb

Selected torque specs

Specs are approximate and listed for the most common cases. Always verify in the workshop manual for your model year and exact engine before final torque.

Fastener	Torque (approximate)	Notes
Engine oil drain plug — 451 M132	~25 Nm	Aluminium sump — do not over-torque. Always new crush washer.
Engine oil drain plug — 453	~25 Nm	Verify per workshop manual
Oil filter cap — 451 cartridge housing	~25 Nm	Verify per workshop manual; plastic housing — torque wrench mandatory
Spark plug — 451 M132	~23 Nm	Anti-seize is debated; clean dry threads + correct torque is the safe path
Spark plug — 453	~25 Nm	Verify per workshop manual
Wheel lug nut / bolt — 451 / 453	~110 Nm	Star pattern, in stages
Wheel lug nut / bolt — 450	~110 Nm	Star pattern, in stages
Brake caliper guide bolt — 451 / 453	~30 Nm	Anti-seize on the slider, not the threads
Brake caliper bracket-to-knuckle bolt	~85-100 Nm (per workshop manual)	Generally a one-time torque; some require new bolts

The "varies" entries above mean the spec is engine-specific or model-year-specific. Don't guess — pull the workshop manual.

What this doesn't cover

Specific torque values for engine internal work (head bolts, main bearings, big-end caps). That's workshop-manual territory, full stop.
Air conditioning refrigerant capacity and oil — varies by build and AC system. Use the under-hood label or workshop manual.
Differential and axle service on the 453 / Forfour. The platform is sealed for normal service life.
Specific approvals for the rare variants (cdi BlueEFFICIENCY, EQ electric, etc.). Those have additional spec callouts that aren't summarized here.

When the cost of being wrong is high — a wrong torque, a wrong coolant — the workshop manual wins over any quick reference, including this one.

Manual references

Browse Smart workshop manuals on smartcarmanuals.com — model-specific reference manuals on the home page; pick your chassis code section for torque specs and detailed procedures.